Sensors are used in the automotive industry to sense amounts of oxygen, hydrocarbons, nitrous oxide (NOx), and other materials present in exhaust gases. Sensors are also used to measure other properties of exhaust gasses, such as temperature. These sensors may include various electrodes, contacts, conductors, structural elements, and other materials and systems. Sensors may also include electrochemical cells, thermocouples, heaters, conduits, various electrodes, particulate detectors, conductivity cells, one or more catalysts or catalytic elements, and the like, either alone or in various combinations. The operational conditions under which such sensors operate may require the sensor to be encased within a package that is capable of allowing the sensor to function despite the vibrations, temperature extremes, and other environmental concerns surrounding components that operate as part of an automotive and/or other exhaust gas system.
To function properly, the sensor must be properly installed and or attached to an exhaust system. Such installation may take place on an assembly line, in an automotive repair facility, or other similar environments. Installation of a sensor may include tightening, welding and/or the like of the sensor into an appropriate location in an exhaust system. Such environments and conditions may not be conducive to gentle handling of such a complicated and potentially fragile device, and the sensors may be dropped, abraded, and/or impacted during installation. To insure that the sensor survives such impacts, the sensor may be drop tested to insure that it survives impacts and other treatments that may be experienced during assembly. One method of impact testing sensors includes drop testing, wherein the sensor is dropped from a distance of about 1 meter onto a hard surface. The sensor is then evaluated for operability after successive drops are made. It is desirable for a sensor to be suitable for use after being dropped five (5) times. This drop test may be repeated using several sensors of a particular design due to the variability of how and where the sensor is exposed to the full impact of the fall during any one test. After the sensor is installed, it is subjected to different destructive forces. For example, the sensor may be subjected to heat radiated by the exhaust system. Radiated heat can cause degradation of the materials used in the sensor. Accordingly, protection of a sensor from otherwise destructive forces prior to, during, and after installation of the sensor would be beneficial.